I’m not sure if this kind of device is right or not, but WiFly-City
claimed to be able to ‘unlocked’ most of locked WiFi Network and
providing you up to 10-times higher transmission distance so you can
actually let your PC/laptop sniffs for WiFi network in the range of 1
kilometers. I certainly won’t believe it until I’ve tried it myself.
However, it would be interesting to be able to get a free WiFi network
access where you’ve no need pay a dime for it.